Purified human chorionic gonadotropin induces apoptosis in breast cancer

Study of hesperetin effect on modulating transcription levels of MLH1 and MSH2 genes in SKBR3 breast cancer cell line

Hesperetin (HSP), a flavonoid, has been validated to modify gene expression and function as an epigenetic agent to stop the development of breast carcinoma cells. HSP was investigated in this research to evaluate the expression of the MLH1 and MSH2 genes in cancerous breast cell lines (SKBR3) and healthy cell lines (MCF-11A) after exposure to different dosages (200, 400, and 600 µM/mL) of HSP. After 48 h of exposure, SKBR3's half-maximal inhibitory concentration was 289.6 µM/mL and MCF-10A's was 855.4 µM/mL. The research found that increasing HSP concentrations were closely correlated with an increase in MLH1 gene levels in the SKBR3 cell line, as shown by median and percentile values. HSP therapy caused the MLH1 gene expression to substantially vary in different groups, and in the SKBR3 cell line, MSH2 gene expressions were elevated in a dose-escalating manner. Moreover, HSP also raised the number of apoptotic cells, with the fraction of apoptotic cells escalating substantially at doses of 400 and 600 µM/mL. The outcomes suggested that HSP has the potential to be utilized as a therapeutic intervention for breast cancer, as it can induce apoptosis and reduce cell viability.

β-hCG-induced mutant BRCA1 ignites drug resistance in susceptible breast tissue

β-hCG expression in breast cancer is highly controversial with reports supporting both protective and tumorigenic effects. It has also been reported that risk of breast cancer at an early age is increased with full-term pregnancies if a woman is a BRCA1 mutation carrier. We have already demonstrated that BRCA1-defective cells express high levels of β-hCG and that when BRCA1 is restored, β-hCG level is reduced. Also, BRCA1 can bind to the promoter and reduce the levels of β-hCG. β-hCG induces tumorigenicity in BRCA1-defective cells by directly binding to TGFBRII and induces TGFBRII-mediated cell proliferation. In this study, we analyzed the mechanism of action of β-hCG on BRCA1 expression and its influence on drug sensitivity in breast cancer cells. We demonstrate that β-hCG induces mutant BRCA1 protein expression in BRCA1 mutant cells; however, in BRCA1 wild-type cells, β-hCG reduced wild-type BRCA1 protein expression. Transcriptionally, β-hCG could induce Slug/LSD1-mediated repression of wild-type and mutant BRCA1 messenger RNA levels. However, β-hCG induces HSP90-mediated stabilization of mutant BRCA1 and hence the overexpression of mutant BRCA1 protein, resulting in partial restoration of homologous recombination repair of damaged DNA. This contributes to drug resistance to HSP90 inhibitor 17AAG in BRCA1-defective cancer cells. A combination of HSP90 inhibitor and TGFBRII inhibitor has shown to sensitize β-hCG expressing BRCA1-defective breast cancers to cell death. Targeting the β-hCG-HSP90-TGFBRII axis could prove an effective treatment strategy for BRCA1-mutated breast tumors.

Cytotoxicity and apoptosis induction in breast cancer, skin cancer and glioblastoma cells by plant extracts

Medicinal plants can be candidate as a common alternative for cancer treatment according to natural landscaping and native plants in each country. The aim of this study was the evaluations of cytotoxicity, apoptosis, and cell cycle arrest induction by using seven leaves extracts of Catharanthus roseus, Calystegia sepium, Berberis integerrima, Mahonia fortunei, Melia azedarach, Plantago major, Betula pendula and one bulb extract of Narcissus tazetta. Extracts were assessed on three cancer cell lines including MCF-7 breast cancer cells, A431 epidermal cell line, and U87-MG glioma cell line that were compared to HGF-1 as normal cells. According to analysis of MTT, methanolic extract of C. sepium leaves increased significantly the rate of cell death in all cancer cell lines when compared to HGF-1 as normal cells. Among different extracts, methanolic extract of C. roseus leaves and methanolic extract of C. sepium leaves indicated a crucial role in apoptosis of cancer cells according to evidences from MTT assay, cell cycle analysis, and apoptosis assay. Doxorubicin has been used as standard drug to compare with IC50 s of different extracts. In addition, the encapsulation of methanolic and ethanolic extracts in small unilamellar vesicles form (SUV) increased the cytotoxicity on cancer cell lines and normal cells. Our results indicated that different extracts can differently affect the cytotoxicity rate in variety of cancer cell lines.

The importance of hCG in human endometrial adenocarcinoma and breast cancer

Human chorionic gonadotropin (hCG) is a peptide hormone which plays an important role during pregnancy. But its impact is not limited to pregnancy; it also influences tumor formation and metastatic outgrowth, especially in endometrial adenocarcinoma and breast cancer. This review summarizes what has been written in the literature about the role of hCG as a tumor marker in these 2 gynecological malignancies and also about the signal transduction pathways in which hCG is involved. HCG can, on the one hand, be a marker for the progression of a malignant disease, and on the other hand, it may be a point for therapeutical intervention, so further research into this molecule would be very much worthwhile.

BRCA1 regulation on β-hCG: a mechanism for tumorigenicity in BRCA1 defective breast cancer

Human chorionic gonadotropin β (β-hCG) has been implicated in breast tumorigenesis. However, the role of this hormone is highly controversial as certain studies suggest it has anti-tumor properties while others have found it to be pro-tumorigenic. To unveil the truth, we have analyzed the expression of β-hCG in breast cancer. We identified for the first time that β-hCG expression is linked to BRCA1 status and its overexpression is seen in BRCA1 mutated breast cancer cells, BRCA1 conditional knockout mouse breast cancer tissues and BRCA1 floxed basal cell carcinoma (BCC) tissues. An analysis of three large, transcriptomic data sets from TCGA (The Cancer Genome Atlas) expression profile confirmed the inverse correlation between BRCA1 and β-hCG in human breast cancer. Using ChIP and luciferase assays, we also demonstrated that the cancer cells with wild-type but not mutant BRCA1 directly repress the expression of β-hCG by binding to its promoter. Further, β-hCG promotes migration and invasion predominantly in BRCA1 mutant breast cancer cells. Interestingly, stable overexpression of β-hCG in BRCA1 mutant but not wild-type breast cancer cells results in the formation of spheres even on monolayer cultures. The cells of these spheres show high expression of both EMT and stem cell markers. Since β-hCG belongs to a cysteine knot family of proteins like TGFβ and TGFβ signaling is deregulated in BRCA1 defective tumors, we checked whether β-hCG can mediate signaling through TGFβRII in BRCA1 mutated cells. We found for the first time that β-hCG can bind and phosphorylate TGFβRII, irrespective of LHCGR status and induce proliferation in BRCA1 defective cells. Our results confirmed that there exists a transcriptional regulation of BRCA1 on β-hCG and BRCA1 mutation promotes β-hCG mediated tumorigenesis through TGFβRII signaling. Thus inhibiting β-hCG-TGFβRII could prove an effective treatment strategy for BRCA1 mutated tumors.

Human Chorionic Gonadotropin and Breast Cancer

Breast cancer is well known as a malignancy being strongly influenced by female steroids. Pregnancy is a protective factor against breast cancer. Human chorionic gonadotropin (HCG) is a candidate hormone which could mediate this antitumoral effect of pregnancy. For this review article, all original research articles on the role of HCG in breast cancer were considered, which are listed in PubMed database and were written in English. The role of HCG in breast cancer seems to be a paradox. Placental heterodimeric HCG acts as a protective agent by imprinting a permanent genomic signature of the mammary gland determining a refractory condition to malignant transformation which is characterized by cellular differentiation, apoptosis and growth inhibition. On the other hand, ectopic expression of β-HCG in various cancer entities is associated with poor prognosis due to its tumor-promoting function. Placental HCG and ectopically expressed β-HCG exert opposite effects on breast tumorigenesis. Therefore, mimicking pregnancy by treatment with HCG is suggested as a strategy for breast cancer prevention, whereas targeting β-HCG expressing tumor cells seems to be an option for breast cancer therapy.

Insights into dovetailing GTD and Cancers

Gestational trophoblastic diseases (GTD) encompass a group of placental tumors which mostly arise due to certain fertilization defects, resulting in the over-proliferation of trophoblasts. The major characteristic of this diseased state is that β-hCG rises up manifold than that is observed during pregnancy. The incidence of GTD when analyzed on a global scale, figures out that there is a greater risk in South-East Asia, the reason of which remains unclear. An insight into any possible correlation of GTD incidence with cancers, other than choriocarcinoma, is being attempted here. Also, we review the recent developments in research on the molecular etiopathology of GTD. This review would render a wider eye towards a new paradigm of thoughts to connect GTD and breast cancer, which has not been into the picture till date.

Human Chorionic Gonadotropin Does Not Correlate with Risk for Maternal Breast Cancer: Results from the Finnish Maternity Cohort

Human chorionic gonadotropin (hCG) is necessary for the maintenance of early pregnancy and promotes normal breast cell differentiation. Administered hCG reduces risk of carcinogen-induced breast cancer in animal models, and higher circulating hCG concentrations were associated with significantly lower long-term risk of breast cancer in a prior nested case-control study. In this study, we investigated early-pregnancy hCG concentrations and subsequent breast cancer risk. We conducted a nested case-control study with 1,191 cases and 2,257 controls (matched on age and date at blood collection) in the Finnish Maternity Cohort, a cohort with serum samples from 98% of pregnancies registered in Finland since 1983. This study included women with a serum sample collected early (<140 days gestation) in their first pregnancy resulting in a live, term birth. Breast cancer cases were identified via the Finnish Cancer Registry. Age at breast cancer diagnosis ranged from 22 to 58 years (mean: 41 years). hCG was measured using a solid-phase competitive chemiluminescence assay. Odds ratios (OR) were calculated using conditional logistic regression. We observed no association between hCG and breast cancer risk, overall [Quartile 4 vs. 1, OR, 1.14; 95% confidence interval (CI), 0.94-1.39], by estrogen and progesterone receptor status, or by ages at first-term birth or diagnosis. Associations did not differ by time between pregnancy and diagnosis (e.g., <5 years, OR_{Q4 vs. Q1}, 1.10; 95% CI, 0.64-1.89; ≥15 years, OR_{Q4 vs. Q1}, 1.36; 95% CI, 0.86-2.13; p_{heterogeneity} = 0.62). This large prospective study does not support an inverse relationship between early pregnancy serum hCG concentrations and breast cancer risk. Cancer Res; 77(1); 134-41. ©2016 AACR.

The controversial role of human chorionic gonadotropin in the development of breast cancer and other types of tumors

INTRODUCTION

Breast cancer is the most often diagnosed tumor of women and one of the leading cause of cancer related death. Due to different known risk factors there are epidemiological differences. Beside genetic disorders and patient's age it is especially the age of the first full-term pregnancy and in this context the pregnancy hormone human chorionic gonadotropin that seems to play an important role.

METHODS

This review is based on a PubMed research in publications of the last 20 years. Only articles in English language were considered.

RESULTS

The effect of human chorionic gonadotropin on development of cancer is controversial. In fact, for breast cancer there is evidence that this hormone has a protective effect against tumorigenesis due the differentiation of the mammary tissue after a full term pregnancy through the downregulation of estrogen receptors.

CONCLUSION

Human chorionic gonadotropin has among promoting pregnancy important controversial functions especially in tumor development. The mechanisms that explain the pro- and anti-carcinogenic effects are not fully understood yet. It seems to have a protective effect on breast cancer through increasing differentiation and hereby decreasing susceptibility of the mammary tissue for toxicants. This knowledge might help developing a preventive agent in the next future that uses the anti-carcinogenic effect of human chorionic gonadotropin and thereby decrease the mortality out of breast cancer.

Relation between parity and pregnancy-related hormones and breast cancer control

SUMMARY 

Epidemiological research has indicated the beneficial effects of full-term pregnancy at an early age for a reduction in breast cancer risk. Experimental data have shown that pregnancy and pregnancy-related hormones, such as estrogen plus progesterone, estrogen alone and human chorionic gonadotropin, are involved in parity-induced protection. Pregnancy and short-duration treatment of a young host with pregnancy-related hormones to mimic the pregnancy environment provide mammary cancer protection by making cells refractory to carcinogenic stimuli and causing growth arrest and programmed cell death. Experimental data concerning pregnancy and pregnancy-related hormones are reviewed in relation to intrinsic subtypes of mammary cancer.

Free β-human chorionic gonadotropin, total human chorionic gonadotropin and maternal risk of breast cancer

BACKGROUND

We investigated whether the free β-human chorionic gonadotropin (free β-hCG) would provide additional information to that provided by total hCG alone and thus be useful in future epidemiological studies relating hCG to maternal breast cancer risk.

MATERIALS & METHODS

Cases (n = 159) and controls (n = 286) were a subset of our previous study within the Northern Sweden Maternity Cohort on total hCG during primiparous pregnancy and breast cancer risk.

RESULTS

The associations between total hCG (hazard ratio: 0.79; 95% CI: 0.49-1.27), free β-hCG (hazard ratio: 0.85; 95% CI: 0.33-2.18) and maternal risk of breast cancer were very similar in all analyses and mutual adjustment for either one had minor effects on the risk estimates.

CONCLUSION

In the absence of a reliable assay on intact hCG, total hCG alone can be used in epidemiological studies investigating hCG and breast cancer risk, as free β-hCG does not appear to provide any additional information.